Although the Google Voice service hasn’t allowed you to change your original Google number, you can now do so–in exchange for $10. Don’t be surprised, you knew Google would piggy-back paid enhancements on top of the free service, didn’t you?

Google Voice, an advanced telephony service, now lets you change your number. Despite the fact that the search giant originally pitched fixed Google Voice numbers, beta users have been pressuring the company to allow the phone number change.

“Maybe you’d prefer to have a local number after moving to another area code,” said Google. “Or maybe you’d just like to find a more personalized number than what you have now to keep for the long term. For situations like these we have added the ability to change your Google Voice number.”

Google transcribes your voicemail.

However, there’s a one-time $10 fee charged for changing your Google phone number, although something tells me it’ll be a small price to pay for people with the pressing need to change or personalize their Google numbers.

The change becomes effective immediately–what a far cry from the last century paper work and bureaucracy involved whenever you asked your landline operator to change your number.

Google will also keep your old Google Voice number in use for another three months so you can update your contacts about the change.

During this transition period, calls and SMS to both numbers will show in your account. Finally, Google will also inform you who’s still calling your old number just before it expires so you can update them individually.

Christian’s opinion

If you haven’t yet checked out the Google Voice service, now is the time (here is a review). Besides the fact that it’s free, Google Voice gives you one phone number that links all your cellphones and fixed lines. This means that your contacts can call only your Google number. You decide where incoming calls route, depending on who’s calling, region, phone number, and other custom settings managed via the web interface. The service is currently available by invite only but existing GrandCentral customers can upgrade to Google Voice by following the link in their account inbox.

The service link all your cellphones and landlines to one Google number.

The key appeal of Google Voice is its free-roaming phone number that follows you wherever you go. It doesn’t matter if you move, change jobs, or switch wireless carries, your Google Voice number always goes where you go. Because only your forwarding phone numbers change, your Google number remains the same. A host of advanced features greatly extend the service appeal, the call forwarding, conference calls on the fly, call switching, voicemail transcripts, etc.

If you ask me, Google Voice is a potential gold mine. I have no doubt in my mind that the service will explode when Google rolls it out to more users in a “matter of weeks” and, especially, to international markets. Because it’s free and convenient, Google Voice certainly appeals to millions. Combining the concept of Google Voice with the Android platform is the next step that could create an entirely new market.

If you ask analysts, the whole point of Google Voice is to extend Google’s footprint in the mobile space. More eyeballs mean more page and ad views, which drives the advertising revenue up. Yup, it’s a revenue game.